Silo dust collection

ABSTRACT

Granular material flows out through the discharge opening of a silo and through a sealed housing to a target location. A vent opening in a top portion of the silo has a vent cover operative to selectively open and close the vent opening. When the vent cover is closed, air movement into an upper portion of the silo is prevented. A gate is operative to control a flow of granular material through the discharge opening. A vacuum conduit has a lower input end thereof connected to an interior of the housing, and an upper output end thereof located in an upper portion of an interior of the silo. Material flowing out of the silo creates a vacuum drawing dust from the housing up the vacuum conduit into the silo.

FIELD OF THE INVENTION

This disclosure relates to the field of granular material storagefacilities and in particular dust collection for storage silos.

BACKGROUND OF THE INVENTION

Silos are commonly used for storing granular material such as sand,cement, salt, fertilizer, and the like. The silos may be installed at apermanent site such as a concrete plant or the like, but often it isdesired to store granular material at temporary work sites such as oilwells and the like. Portable storage silos are well known in variousindustries for temporary on-site storage of various granular materials.The empty silos are transported to a work site and supported suitably toaccommodate the weight of the granular material being stored, and thenthe silo filled with granular material.

These silos are commonly oriented vertically to maximize the quantity ofmaterial stored above a hoppered bottom such that the dry material willflow out by gravity through a discharge opening with a gate that can beopened or closed to control flow out of the silo. Portable silos areoften transported to the work site in a lowered horizontal transportorientation, and then raised to a vertical working orientation at thework site for similar reasons.

It is common for such storage silos, permanent or portable, to include aloading conduit to allow connection to discharge pipes of a pneumaticconveyor on a transport vehicle such that granular material can beconveyed into the silo by the pneumatic conveyor. Such pneumaticconveyors typically comprise a blower operative to create an air streamin a conveyor pipe connected to a storage vessel on the transportvehicle to receive a flow of granular material that mixes with the airstream and is carried along the conveyor pipe to an output end thereof

A lower input end of the loading conduit is connected to the output endof the conveyor pipe, and the air stream and granular material mixedtherein move through the loading conduit to a discharge end of theloading conduit located in an upper portion of the storage silo wherethe granular material falls out of the air stream into the silo. The topof the silo includes vents to allow the air stream entering the silo toescape.

When transferring granular material into such silos a considerableamount of dust is often generated, depending on the nature of thegranular material. This dust has conventionally simply been vented outinto the atmosphere with the air stream however more recently it hasbeen recognized that the dust presents a health hazard to workers at thesite, and efforts have been made to control the dust by filtering theescaping air stream.

Dust similarly is generated when the granular material flows out of thedischarge opening. The granular material often discharges through achute which directs the material into a conveyor or like targetlocation. The flow of granular material along the chute, and thegranular material landing on the target location generate considerabledust as well. Granular material is often drawn out of these silos athigh rates, for example 500 or more cubic feet per minute, such thatwhen drawing material out of the silo air passes from the atmospherethrough the vents into the silo at a rate substantially the same as therate of material removal.

SUMMARY OF THE INVENTION

The present disclosure provides a granular material storage silo systemthat overcomes problems in the prior art.

In a first embodiment the present disclosure provides a granularmaterial storage silo apparatus comprising a silo with a dischargeopening at a bottom portion thereof configured such that granularmaterial flows out through the discharge opening and through a sealedhousing to a target location. A vent opening in a top portion of thesilo has a vent cover operative to selectively open and close the ventopening. When the vent cover is closed, air movement into an upperportion of the silo is prevented. A gate is operative to control a flowof granular material through the discharge opening. A vacuum conduit hasa lower input end thereof connected to an interior of the housing, andan upper output end thereof located in an upper portion of an interiorof the silo.

In a second embodiment the present disclosure provides a kit forcollecting dust when removing granular material from a silo with adischarge opening at a bottom portion thereof configured such thatgranular material flows out through the discharge opening to a targetlocation, and with a loading conduit mounted to the silo with a lowerinput end located at a lower location on an exterior of the silo and anupper output end located in an upper portion of an interior of the silo.The kit comprises a sealed housing enclosing a flow path between thedischarge opening and the target location, a dust conduit connected atan input end thereof to an interior of the housing, and connectable atan output end thereof to the lower input end of the loading conduit, andvent covers operative to close vent openings in an upper portion of thesilo and prevent air movement into the upper portion of the silo.

In a third embodiment the present disclosure provides a method ofcollecting dust when removing granular material from a silo with a ventopening in an upper portion of the silo and a discharge opening at abottom portion of the silo configured such that granular material in thesilo flows out through the discharge opening to a target location. Themethod comprises enclosing a flow path between the discharge opening andthe target location with a sealed housing; connecting a vacuum conduitat an input end thereof to an interior of the housing, and locating anupper output end of the vacuum conduit in an upper portion of aninterior of the silo; closing the vent opening to prevent air movementinto the upper portion of the silo above the granular material in thesilo; operating a gate to release a flow of granular material throughthe discharge opening such that granular material flowing out thedischarge opening creates a vacuum in the upper portion of the siloabove the granular material therein and draws air and dust from thehousing into the vacuum conduit and through the vacuum conduit into theupper portion of the silo.

In the present disclosure, dust is collected when removing granularmaterial from a silo by using the vacuum created when granular materialis drawn out of the silo to draw air and dust out of the housingenclosing the granular material flow and transfer the dust back into thesilo through a vacuum conduit. The loading conduit that is commonlyinstalled on granular material storage silos can conveniently provide alarge part of the vacuum conduit. It is common for granular material tobe drawn out of such silos at fairly high rates requiring thereplacement in the silo above the granular material therein of a similarrate of air, thus creating an air stream sufficient to draw dust out ofthe sealed housing. The air stream flow can be increased by adding anexhaust fan to draw more air out of the silo above the granularmaterial.

BRIEF DESCRIPTION OF THE DRAWINGS

While the invention is claimed in the concluding portions hereof,preferred embodiments are provided in the accompanying detaileddescription which may be best understood in conjunction with theaccompanying diagrams where like parts in each of the several diagramsare labeled with like numbers, and where:

FIG. 1 is a schematic cut-away side view of an embodiment of a granularmaterial storage silo apparatus of the present disclosure with granularmaterial being removed from the silo;

FIG. 2 is a schematic cut-away side view of the embodiment of FIG. 1with granular material being transferred from a transport vehicle intothe silo;

FIG. 3 is a schematic cut-away side view of a further embodiment of agranular material storage silo apparatus of the present disclosure;

FIG. 4 is a schematic cut-away side view of the valve mechanism of theembodiment of FIG. 3; and

FIG. 5 is a schematic side view of a dust conduit with a valve mechanismon the output end thereof, the valve mechanism connected to the lowerinput end of the loading conduit, and to the output pipe of a pneumaticconveyor.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 schematically illustrate an embodiment of a granularmaterial storage silo apparatus 1 of the present disclosure. In FIG. 1granular material is being removed from the silo 3 of the apparatus 1,and in FIG. 2 granular material is being loaded into the silo 3.

The apparatus 1 comprises a silo 3 with a discharge opening 5 at abottom portion thereof configured such that granular material 7 flowsout through the discharge opening 5 and through a sealed housing 9 to atarget location 11. In the illustrated apparatus 1 the housing 9 has afloor 13 sloped such that the granular material 7 flows along the slopedfloor 13, and the housing 9 is sealed to the silo wall 15 over the gate17 that controls flow of granular material 7 through the dischargeopening 5 such that no air can enter the housing 9 except though theoutput end 19 of the housing 9.

The illustrated silo 3 is a typical silo with a vent opening 21 definedin a top portion of the silo 3, and a loading conduit 23 with a lowerinput end 25 located at a lower location on an exterior of the silo 3and configured to be attached to a pneumatic conveyor output, and anupper output end 27 located in an upper portion of an interior of thesilo 3.

A vent cover 29 is operative to selectively open and close the ventopening 21. When the vent cover 29 is closed, as seen in FIG. 1, airmovement into the upper portion of the silo 3 is prevented. A filter 30also covers the vent opening 21, such that dust is removed from airleaving the vent when the cover 29 is open.

To draw dust out of the housing 9 a vacuum conduit, illustrated as anexterior pipe 20, has a lower input end 22 thereof connected to aninterior of the housing 9, and an upper output end 24 thereof located inan upper portion of an interior of the silo 3. The pipe 20 could be onthe interior of the silo as well if desired. The vacuum conduit can thusbe provided as schematically illustrated in FIGS. 1 and 2 simply byinstalling a separate conduit 20 on the silo 3 connecting the interiorof the housing 9 to the upper interior of the silo 3. A valve or cap maybe provided to close the pipe 20 to prevent movement of airtherethrough. As granular material is drawn out of the silo 3, a vacuumwill be created in the upper portion of the silo 3 above the granularmaterial and air and dust will be drawn from the housing 9 through thevacuum conduit into the silo 3.

It may, however, often be more convenient and economical to use theloading conduit 23, which is commonly available on silos fortransferring granular material from a transport vehicle into the silowith a pneumatic conveyor, to form a portion of the vacuum conduit, sothat only a shorter dust conduit 31 is required to complete the vacuumconduit.

In the apparatus 1 of FIGS. 1 and 2 the dust conduit 31 is connected atan input end 33 thereof to an interior of the housing 9. The input end33 is connected to the interior of the housing 9 at a location abovegranular material 7 flowing along the sloped floor 13. The dust conduit31 is connectable at an output end 35 thereof to a lower portion of theloading conduit 23 and when the output end 35 of the dust conduit 31 isconnected to the loading conduit, the lower input end 25 of the loadingconduit 23 is sealed such that no air can enter through the lower inputend. The vacuum conduit is thus conveniently provided by the dustconduit 31 and loading conduit 23 connected together to form therequired conduit path between the interior of the housing 9 and theupper portion of the interior of the silo 3.

Connecting the output end 35 of the dust conduit to a lower portion ofthe loading conduit 23 and sealing the lower input end 25 of the loadingconduit 23 may be accomplished in a variety of ways. In the illustratedapparatus 1, the output end 35 of the dust conduit 31 is simplyconnected directly to the lower input end 25 of the loading conduit 23such that the connection is made and the lower input end 25 of theloading conduit 27 is sealed by the output end 35 of the dust conduit31.

In the apparatus 1 illustrated in FIGS. 1 and 2 the target location isillustrated as a belt conveyor 37 with a grate 39 over the top thereof.The housing 9 includes a flexible fabric portion 41 at the output endthereof which maintains the enclosure of the stream of granular material7 flowing from the discharge opening 5, as schematically illustrated inFIG. 1, until the granular material 7 falls through the grate 39 ontothe conveyor 37.

The present disclosure thus provides a method of collecting dust whenremoving granular material 7 from a silo 3 with a discharge opening 5 ata bottom portion thereof configured such that granular material 7 flowsout through the discharge opening 5 to a target location 11, and with aloading conduit 23 mounted to the silo with a lower input end 25 locatedat a lower location on an exterior of the silo 3 and an upper output end27 located in an upper portion of an interior of the silo 3. The methodcomprises enclosing a flow path between the discharge opening and thetarget location with a sealed housing 9; connecting a vacuum conduit,such as pipe 20 at an input end 22 thereof to an interior of the housing9, and locating an upper output end 24 of the vacuum conduit pipe 20 inan upper portion of an interior of the silo 3; closing the vent opening21 to prevent air movement into the upper portion of the silo 3 abovethe granular material 7 in the silo 3; operating a gate 17 to release aflow of granular material 7 through the discharge opening 5 such thatgranular material 7 flowing out the discharge opening creates a vacuumin the upper portion of the silo 7 above the granular material 7 thereinand draws air and dust from the housing 9 into the vacuum conduit pipe20 and through the vacuum conduit pipe 20 into the upper portion of thesilo 3.

Instead of adding a pipe 20, the vacuum conduit can be convenientlyprovided by connecting a dust conduit 31 at an input end 33 thereof toan interior of the housing 9 and connecting the output end 35 of thedust conduit 31 to a lower portion of the loading conduit 23.

To add granular material to the silo, the lower input end 25 of theloading conduit is connected to an output pipe 43 of a pneumaticconveyor 45 and the pneumatic conveyor 45 transfers granular materialfrom a transport vehicle 47 into the interior of the silo 3 through theloading conduit 23 while releasing air through a vent 23 in an upperportion of the silo 3, as schematically illustrated in FIG. 2.

When a desired quantity of granular material 7 has been transferred, thevent cover 29 is closed to close the vent opening 21 and prevent airmovement into the upper portion of the silo 3 above the granularmaterial 7, and the lower input end 25 of the loading conduit 23 isdisconnected from the output pipe 43 of the pneumatic conveyor 45; andthe output end 35 of the dust conduit 31 is connected to a lower portionof the loading conduit 23 and the lower input end 25 of the loadingconduit 23 is sealed such that together the dust conduit 31 and loadingconduit 23 form the vacuum conduit.

The present disclosure also provides a kit for collecting dust whenremoving granular material from a typical silo 3 as illustrated with adischarge opening 5 at a bottom portion thereof configured such thatgranular material 7 flows out through the discharge opening 5 to atarget location 11, and with a loading conduit 23 mounted to the silo 3with a lower input end 25 located at a lower location on an exterior ofthe silo 3 and an upper output end 27 located in an upper portion of aninterior of the silo 3. The kit comprises a sealed housing 9 enclosing aflow path between the discharge opening 5 and the target location 5. Thehousing 9 can be provided by, for example, air impermeable plasticsheeting fastened over the discharge gate 17 and any discharge chutethat may be present, to provide a sealed enclosure between the dischargegate and 5 and the output end 19 of the housing 9.

A dust conduit 31 is connected at an input end 33 thereof to an interiorof the housing 9, and is configured at an output end thereof the same asa pneumatic conveyor output so same is readily connectable to the lowerinput end of the loading conduit. Vent covers may be required to closevent openings in an upper portion of the silo and prevent air movementinto the upper portion of the silo if the existing silo does not alreadyhave such covers.

FIG. 3 schematically illustrates an alternate embodiment of the granularmaterial storage silo apparatus 101 of the present disclosure where theinput end 133 of the dust conduit 131 is connected to the housing 109and the output end 135 of the dust conduit 131 is connected to the lowerportion of the loading conduit 123 through a valve mechanism 151operative to selectively connect and disconnect the output end 135 ofthe dust conduit 131 and the lower portion of the loading conduit 123,and operative to correspondingly seal and open the lower input end 125of the loading conduit 123.

The valve mechanism 151 is schematically illustrated in FIG. 4, with aflap 153 that moves from position A, where the output end 135 of thedust conduit 131 is connected to the loading conduit 123 and the lowerinput end 125 of the loading conduit 123 is sealed, to position B wherethe output end 135 of the dust conduit 131 is disconnected from theloading conduit 123, and closed to the loading conduit 123, and thelower input end 125 of the loading conduit 123 is open such that thepneumatic conveyor can be connected to transfer granular material intothe silo 103.

The kit of the present disclosure can conveniently include, asschematically illustrated in FIG. 5, a valve mechanism 251 on the outputend 235 of the dust conduit 231 that is adapted to connect to the lowerinput end 225 of the loading conduit 223, and to connect to a pneumaticconveyor output pipe 243. The valve mechanism 251 operates in a mannerthe same as described above for valve mechanism 151, and is convenientlyconnects the dust conduit 231 of the kit to the loading conduit 223 ofan existing silo.

The apparatus 101 further includes an exhaust fan 155 operative to drawair out of the upper portion of the interior of the silo 103. Theillustrated fan 155 draws air out through a filter 130 and through aone-way check valve 157 that allows air to move out of the silo 103, butprevents air from moving into the silo 103, thus maintaining a sealedupper silo portion where a vacuum can be developed by granular materialflowing out of the silo 103.

The present disclosure provides dust control using only the vacuumnaturally created when granular material is drawn out of the silo todraw air and dust out of the housing enclosing the granular materialflow and transfer the dust back into the silo through a vacuum conduit.It is common for granular material to be drawn out of such silos atrates between 200 and 500 cubic feet per minute, or more, requiring thereplacement in the silo above the granular material therein of a similarrate of air, thus creating an air stream sufficient to draw dust out ofthe sealed housing. The air stream flow can be increased by adding anexhaust fan to draw more air out of the silo above the granularmaterial. The loading conduit commonly installed on such granularmaterial storage silos can be utilized to form a large part of therequired vacuum conduit.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous changes and modifications willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all such suitable changes or modificationsin structure or operation which may be resorted to are intended to fallwithin the scope of the claimed invention.

1. A granular material storage silo apparatus comprising: a silo with adischarge opening at a bottom portion thereof configured such thatgranular material flows out through the discharge opening and through asealed housing to a target location; a vent opening in a top portion ofthe silo, and a vent cover operative to selectively open and close thevent opening, and wherein when the vent cover is closed, air movementinto an upper portion of the silo is prevented; a gate operative tocontrol a flow of granular material through the discharge opening; and avacuum conduit with a lower input end thereof connected to an interiorof the housing, and an upper output end thereof located in an upperportion of an interior of the silo.
 2. The apparatus of claim 1comprising a loading conduit with a lower input end located at a lowerlocation on an exterior of the silo and configured to be attached to apneumatic conveyor output, and an upper output end located in the upperportion of the interior of the silo, and a dust conduit connected at aninput end thereof to an interior of the housing and connectable at anoutput end thereof to a lower portion of the loading conduit, andwherein the vacuum conduit is provided by connecting the output end ofthe dust conduit to the lower portion of the loading conduit and sealingthe lower input end of the loading conduit.
 3. The apparatus of claim 2wherein the output end of the dust conduit is connectable to the lowerinput end of the loading conduit such that the lower input end of theloading conduit is sealed by the output end of the dust conduit.
 4. Theapparatus of any one of claims 2 and 3 claim 2 wherein the output end ofthe dust conduit is connected to the lower portion of the loadingconduit through a valve mechanism operative to selectively connect anddisconnect the output end of the dust conduit and the lower portion ofthe loading conduit, and operative to correspondingly seal and open thelower input end of the loading conduit.
 5. The apparatus of claim 1wherein the housing includes a flexible fabric portion at an output endthereof.
 6. The apparatus of claim 1 further comprising an exhaust fanoperative to draw air out of the upper portion of the interior of thesilo.
 7. The apparatus of claim 6 wherein the exhaust fan draws air outof the upper portion of the interior of the silo through a filter. 8.The apparatus of claim 1 wherein the housing has a floor sloped suchthat the granular material flows along the sloped floor, and wherein thelower input end of the vacuum conduit is connected to the interior ofthe housing at a location above granular material flowing along thesloped floor.
 9. A kit for collecting dust when removing granularmaterial from a silo with a discharge opening at a bottom portionthereof configured such that granular material flows out through thedischarge opening to a target location, and with a loading conduitmounted to the silo with a lower input end located at a lower locationon an exterior of the silo and an upper output end located in an upperportion of an interior of the silo; the kit comprising: a sealed housingenclosing a flow path between the discharge opening and the targetlocation; a dust conduit connected at an input end thereof to aninterior of the housing, and connectable at an output end thereof to thelower input end of the loading conduit; and vent covers operative toclose vent openings in an upper portion of the silo and prevent airmovement into the upper portion of the silo.
 10. A method of collectingdust when removing granular material from a silo with a vent opening inan upper portion of the silo and a discharge opening at a bottom portionof the silo configured such that granular material in the silo flows outthrough the discharge opening to a target location, the methodcomprising: enclosing a flow path between the discharge opening and thetarget location with a sealed housing; connecting a vacuum conduit at aninput end thereof to an interior of the housing, and locating an upperoutput end of the vacuum conduit in an upper portion of an interior ofthe silo; closing the vent opening to prevent air movement into theupper portion of the silo above the granular material in the silo;operating a gate to release a flow of granular material through thedischarge opening such that granular material flowing out the dischargeopening creates a vacuum in the upper portion of the silo above thegranular material therein and draws air and dust from the housing intothe vacuum conduit and through the vacuum conduit into the upper portionof the silo.
 11. The method of claim 10 wherein the silo comprises aloading conduit mounted to the silo with a lower input end thereoflocated at a lower location on an exterior of the silo and an upperoutput end located in the upper portion of the interior of the silo, andwherein the vacuum conduit is provided by connecting an input end of adust conduit to an interior of the housing and connecting an output endof the dust conduit to a lower portion of the loading conduit, andsealing the lower input end of the loading conduit.
 12. The method ofclaim 11 comprising connecting the output end of the dust conduit to thelower input end of the loading conduit to seal the lower input end ofthe loading conduit.
 13. The method of claim 10 further comprisingdrawing air through a filter and out of the upper portion of the silowith an exhaust fan to increase a volume of air flowing through the dustconduit.